This invention relates to the field of apparatus for improving speech or singing by enhancing feedback from a user's mouth to the user's ear.
There are times when it's helpful to hear oneself better--for example when singing as part of a chorus or when one's hearing is impaired. We hear our own voice by a combination of vibrations conducted through flesh and bone directly to the inner ear and cochlea, and by back-scattering, refraction or distant reflection of sound waves emanating from our mouth. Hearing aids--and previously, ear trumpets--augment hearing generally, but with no intent to selectively provide personal feedback. However, when air-transmitted hearing is overwhelmed by ambient sound or impaired by sound absorption or reduced ear sensitivity, it is a great benefit to enhance feedback.
Prior art includes numerous inventions meant for hearing distant sounds more clearly. Examples include U.S. Pat. Nos. 3,618,698 to McCabe (1971), 3,938,616 to Brownfield (1976), 4,997,056 to Riley (1991), and 5,345,512 to Lee (1994). In all cases, these direct their efforts to hearing remote sounds, specifically from in front of the user. To varying degrees, these also incorporate adjustment, mounting or alignment features to fit individual heads and to direct sound from a distance into a user's ears.
Electronics has engendered elaborate and expensive systems for personal feedback, involving (at the least) a microphone, amplifier, headphones and associated cabling. With these, and a source of power, the function of feedback may be fulfilled. One such system is the so-called Voice Imaging system by Voice Imaging, Incorporated; another is the ADDVOX III by Bruce Medical Supply. Others are disclosed in U.S. Pat. Nos. 4,732,072 (1988) to Garlock, 4,321,853 (1982) to Tumblin, 5,557,056 to Hong (1996), 5,565,639 to Bae (1996), and 5,061,186 to Jost (1991), roughly in order of their increasing complexity.
All of these suffer from intricacy, high cost, and the need for a source of power.
A variety of improvisations, such as cupping a hand to the cheek, cutting a crude shape from a milk container or making a sound pipe from pieces of commercially available tubing, has been contrived to fill the need for personal feedback. The only prior art directed to the purpose of personal feedback is a product named Tok-Back--a single piece kidney-shaped molding of thin, soft elastomeric material formed to cover and enclose the user's ears, mouth, cheeks and chin to trap sound pressure emanating from the mouth. As such, it is cumbersome, awkward, unsanitary and obtrusive to use, requires periodic repositioning on the face and suffers from extreme internal resonances.